STUPID thing to celebrate in the USA.
Cinco de Mayo, or the fifth of May, is a holiday that celebrates the date of the Mexican army’s May 5, 1862 victory over France at the Battle of Puebla during the Franco-Mexican War. The day, which falls on Tuesday, May 5 in 2020, is also known as Battle of Puebla Day. While it is a relatively minor holiday in Mexico, in the United States, Cinco de Mayo has evolved into a commemoration of Mexican culture and heritage, particularly in areas with large Mexican-American populations.
https://www.history.com/topics/holidays/cinco-de-mayo